Drying apparatus



Sept. 12, 1933. B. M. HESS 1, 6

' DRYING APPAfiATus Filed July 17, 1929 s Sheets-Sheet 1 54 15 30 ",n I 261 A26 B.M.HESS

DRYING APPARATUS Filed July 17, 1929 5 Sheets-Sheet 2 lrlfflfrfl V sept 12, 1933. B M 555 132%,???

DRYING AFPARATUS Filed July 17', 1929 S-Sheets-Sheet 3 Sept. 12, 1933. M HESS I 1,926,772

DRYING APPARATUS Filed July- 17. 1929 5 Sheets-Sheet 5 atented s 1219 33 UNIT-ED STATES-PATENT OFFICE DRYING APPARATUS Bryce M. Hess, Chicago, Ill.

Application July 17, 1929. Serial No. 378,933

4 Claims. (Cl. 34-34) My invention relates, more particularly, to the the conduit forming a part oi the course through drying of material, asfor example, and more which the products of combustion from a furespecially, grain. nace, forming a part oi the apparatus, are di- One of my objects is to provide means whererooted to the drying chamber portion of the ap- 5 by should the temperature in the drying portion paratus.

of the apparatus become highly excessive and Figure 4 is a Section taken at th line 4 011 particularly where spontaneous combusion of the 3 and viewed in the direction of the arrow. material occurs, the flow of drying medium Figure 5 is a broken enlarged plan view taken thereto will be automatically discontinued. at t e i 5 o i 1 a viewed in the direc- Another object is to provide, in a drying appation of the arrow. ratus comprising a furnace supplying the drying Figure 6 is a view in vertical sectional elevaheat, for utilizing all of the heat produced by the tion of one of the similar damper controlling mofurnace and in the most direct manner to the tors forming parts of the apparatus. end that the drying operation may be performed Figure '1 is a view somewhat in the nature oi a with the minimum amount of fuel and thus with diagram of the mechanism for automatically greater economy. shutting oil the supply of air to the drying cham- Another object is to provide in a drying appaher in the event 01 a highly excessive temperature ratus of the character above stated, for the mixtherein; and ture of the hot gases of combustion and the air 8, a similar view of a modification of without requiring the use of metal tubes located the control mechanism shown in Fig. 7. in the furnace and subjected to the hot products In the particular apparatus illustrated 9 repof combustion and through which the air, out 01' resents the enclosing walls of a grain drier shown communication with the interior of the furnace, as provided at its upper end with a feed hopper 25 passes for superheating, or other metallic radiat- 10 for receiving the material to be dried. Below ing surface subjected to radiant heat from the the-hopper 10 are drying racks represented genfurnace, the use of such tubes or. radiating surerally at 11 and below the drying racks are coolfaces presenting a disadvantage in that they ing racks represented at 12. often become burned out or warped and disturb These racks may be of any desired construc- 30 the normal functioning of the apparatus. tlon, as for example as shown in United States Another object is to provide an apparatus in Letters Patent No. 1,210,166 granted to George which the temperature inthe drying spacewillbe -H. Hess, December 26, 1916, and serve to hold maintained substantially uniform regardless of the material to be dried and thereafter cooled, sharp fluctuations in the temperature of the hot and through which the material gravitates to the 35 gases supplied to the mixing chamber from the hopper outlet 13 at the desired speed by any feedfurnace. controlling mechanism, as for example as dis- Another object is to reduce the heat losses in closed in said patentt apparatus of the general character above stated. The drying racks 11 are arranged parallel with Another object is to provide for the maintaineach other and in a horizontal series in spaced do ing of a substantially uniform temperature in relation, as shown in Fig. 5, the racks 12 constithe drying space regardless of the degree oi'temtilting a downward continuation of the racks perature required for the drying operation. 11. The spaces between the racks 11 are closed- Another object is to provide, in a drying appaat their upper ends by peaked partitions 14 and ratus comprising a furnace supplying the drying also closed adjacent the junctures of the racks 5 heat, for the automatic control of the combus- 11 and 12 by similarpartitions. 10o

titan-supporting air to the furnace responsive to As shown insald patent the opposed side walls temperature conditions in the drying portion of of the racks 11 and 12 are of openwork form the apparatus; and other objects as will be manas by constructing them of louvered plates which ifest from the following description. serve to retain the grain within the confines o1 50 Referring to the accompanying drawings: the racks while permitting of the passage of air Figure 1 is a view in vertical sectional elevathrough them. tion of drying apparatus embodying my imo Alternate ones of the spaces between the racks provements. r 11 and 12 at the left-hand ends thereof in Fig, 1 Figure 2 is a similar view of certain details oi are closed by imperforate end walls, their oppo- 55 h apparatus 0! F 8- site ends being open, the others of said spaces no Figure 3 is a similar view 01' the lower end oi being closedby imperiorate walls at the righthand ends thereof in 1 with their opposite ends open.

The open ends of these spaces at the righthand ends thereof in Fig. 1 communicate, respectively, with compartments 15 and 16, separated by a partition 17 and in which the racks 11 and 12, respectively, are located, the end walls of these compartments containing openings 18 and 19, respectively, to the atmosphere.

It will be understood from the foregoing that air supplied, as hereinafter described, to the open ends of the spaces between the racks 11 and between the racks 12 will pass through. the apertured sides of the racks 11 and 12 and the grain interposed therebetween thus exerting on the grain a drying or cooling action, as the case may be.

Located in the compartment 15 at the lefthand side of Fig. 1 is a blower 20 the outlet of which communicates, with a series of ducts 21 which communicate, respectively, with those of the spaces between the racks 11 which are open at this end of the structure; and located in the compartment 16, at the left-hand side of Fig. 1, is a suction blower 22 the inlet of which communicates with this end of the compartment 16 and thus with those of the spaces between the racks 12 which are in communication with this portion of the compartment, the outlet of the blower 22 being represented at 23.

In the particular construction shown the source of heated gaseous medium for drying the. grain in the racks 11 is a furnace represented at 24 and which may be of any desired construction, the illustrated arrangement utilizing the hot products of combustion from the furnace, as the gaseous medium referred to.

The furnace shown is of the coal burning type comprising a combustion chamber 25 above a grate 26, with the space 27 below the grate in communication withan air inlet 28 controlled by a hinged door 29 and through which the air for supporting combustion of the fuel is intro duced into the furnace.

Opening at its lower end into the outlet 30 of the combustion chamber 25 is a pipe 31 provided with a slide damper 32, this pipe, which.

is open at its upper end as indicated at 33, being surrounded by a pipe 34 concentrically disposed relative to the pipe 31 and spaced therefrom as shown, the pipe 34 containing series of louveredopenings as represented at 35 for the admission of air, from the atmosphere, into this pipe, and the pipe 31 communicating with a smoke pipe 36 containing a damper 3'7.

The upper end of the pipe 34, which extends above the upper end of the pipe 33 opens into a pipe 38 between the ends of the latter, the pipe 38 communicating at one end with the atmosphere as represented at 39 and at its opposite end opening into the suction inlet of the blower 20.

The apparatus shown comprises means for automaticalw regulating the temperature in the drying portion of the apparatm, these means comprising dampers 40 rotatably mounted at shafts 41 in the upper end oi the pipe 34, above the upper end 33 of the pipe 31, and a series of dampers 42 rotatably mounted at shafts 43 in the pipe 33 between the point at which the pipe 34 opens into the pipe 38 and the inlet 39 oi the latter.

The shafts ll are connected with levers 44 and 45 which are pivotally connected together by a link 46; and the shafts 43 are connected with levers 47 pivotally connected together by a link 48. One of the shafts 43 is provided with another lever 49 which is connected with the lever 45 by a link 50, the latter being pivotally connected with both of these levers.

The arrangement of the dampers 40 and 42,

together with the lever connections between them, are such that as the dampers 40 move toward closed position the dampers 42 move to- ,ward open position, and vice versa.

The simultaneous movement of the dampers 40 and 42- as stated, responsive to temperature variations in the drying portion of the apparatus, is controlled by a motor represented at 51 and comprising a lever 52 fulcrumed between its ends on a stationary support 53 and pivotally connected adjacent" one end, as represented at 54, with one end of a link 55 the other end of which is pivotally connected at 56 with an ex-' tension 57 of the lever 44.

A spring 58 operates, unless restrained, to rock the lever 52 in a direction for closing the dampers 40 and opening the dampers 42.

The lever 52 between its fulcrum 53 and the connection thereof with the spring 58 operatively engages, through a pivoted link 59, the outer end of a rod 60 connected with the free end of a bellows diaphragm 61 the opposite end of which 'is secured to a wall of a casing 62 containing an opening to receive a pipe 63 "which communicates with the fixed end of the diaphragm 61. The pipe 63 opens into a pipe 64 which leads from any suitable source of compressed air, as for example a compressed air tank represented at 65. the pipe 64 being provided between the tank 65 andthe point at which it communicates with the pipe '63.,-with a constriction which may be produced by adjusting the stem 66 of a valve 67.

The pipe 64 continues upwardly and opens into a device, represented diagrammatically at 68 and preferably located in one of the racks 11, for releasing the pressure in the pipe 64 at its upper end responsive to the rise in temperature in the drying portion of the apparatus above that desired to be maintained, and proportionately to such excess of temperature.

The device 68 may be of any desired construction such, as for example, that commonly used in heat-controlling systems and comprising a valve cooperating with the open end of the air-- pipe (the pipe 64) and operatively engaged, and controlled, by a thermostatic element such as a bar which lengthens under increase of heat and opens the valve.

In the operation of the apparatus the air pressure from the tank 65 builds up in the diaphragm 61 causing the latter to assume the position shown in Figs. 1 and 6 in which position the dampers 46 are open and the dampers 42 are closed, whereby hot products oi combustion from the furnace, mingled with air drawn into the pipe 34 through the opeiungs 35 therein, diluted substantially to the m nimum, are caused,

by the action of the blower 26, to be forced the gaseous medium-supplied to the drying racks bytheb1ow'er'20.

It is also desirable that the supply of hir to the furnace .through the air inlet 28 be automaticaly varied responsive to the temperature condition in the racks 11. To this end the door 29 is shown as connected with the lever 52 by a cable 69 shown as passing over stationary pulleys whereby should the temperature in the appara= ftus become greatly excessive as for example in the event that spontaneous combustion of the material occurs, the flow of gaseous medium to the drying racks 11 is arrested, these means, in the particular construction shown, comprising a series of dampers 72 located in the pipe 38 be- .tween the dampers 40 and '42 and the blower 20 and mounted on rotatable shafts '73, these shafts being connected with levers '14 pivotally connected with a link 75, which latter is pivotally connected with a link '76 in turn pivotally connected at '77 with one end of a lever 78 fulcrumed between its ends at 79 on a stationary support.

The other end of the lever '78 is connected with a spring 80 which. unless restrained, rocks the lever 78 to a position in which the dampers 72 are closed,'as shown by dotted lines in Fig. 2.

Means are provided for normally holding the lever '78 in the position shown, and in opposition to the action of the spring 80 in which position the dampers '72 are open, these means comprising the same mechanism as that shown in Fig. 6, the bellows diaphragm of which opens into a pipe 81 which communicates with the pipe 64 between the tank 65 and the valve 6'7, and extends upwardly to a header 82 provided with branch pipes 83 of any suitable number each equipped with any suitable form of device represented at 84 and shown as located above certain of the partitions 14, which operates to release the pressure in the pipe 81 in the event of the rise of temperature in the drying portion of the apparatus to the high degree at which it is desired the flow of gaseous medium to the racks 11, be arrested.

By way of example the devices 84 may be of the fusible type commonly employed in automatic sprinkler systems which operate when subjected to excessive temperature to open to the atmosphere the pipes with which they are connected, by the fusing, under excessive heat, oi elements which normally maintain the devices in closed condition.

when the pressure in the pipe 81 becomes reduced by the opening of any one of the devices 84, the spring 80 operates to close the dampers '72 thereby closing the pipe 38 to the atmosphere and to the source of heating medium.

It is also desirable that the blower. 20 and suction fan 22 be automatically stopped in the event of the occurrence of such excessive'heat in the apparatus as to open the air line at any one of the devices 84, the apparatus shown also eflecting this operation.

In Fig. '7 I have illustrated, somewhat diagrammatically, an arrangement whereby simultaneous closing of the dampers 72 are effected. In this arrangement the motor for operating the blower 20'is represented at 85 and the motor for operating the suction fan 22 is represented at 86. The line wires through which current is supplied to the motors are represented at 87 and 88 these wires being connected with the movable double arm 89 of a switch, the stationary contacts of which are represented at 90 and 91 and connect with the terminals of the motor. The motor 86 is arranged inparallel with the motor 85 by wires 92 and 93 connected with the line wires 87 and 88, respectively, the wires 92 and 93 having interposed therein another switch device the stationary contacts of which are represented at 95 and 96 and are connected with the terminals of the motor 86 and the double movable arm of which is represented at 94.

The two switches referred to are provided with portions 9'1 and 98 of magnetic material and cooperate with springs 99 and 100, respectively, which tend to hold these switches open. Cooperating with the members 97 and 98 are electromagnets 101 and 102, respectively, which serve to hold the switches closed, against opening under the action of the springs, after the closing of the switches in any desirable way. The current for energizing the ele'ctromagnets 101 and 102. is supplied from a transformer 103 the primary of which and represented at 104 is connected with the wires leading from the switch 89 to the motor 85 and the secondary of which 105 represented at 104 connects with the winding of the magnet 101 by wires 105 and 106 and with the winding of the magnet 102 by wires 107 and 108 connected with-the wires 105 and 106.

The arrangement shown also comprises a cir- 110 cuit for short circuiting the secondary 104 responsive to the opening of any one of the devices 84 the means shown comprising a switch device represented at 109, thespring fingers 110 and 111 of which are normally separated and are mm nected with the wires @105 and 106 by wires 112 and 113, respectivey.

The lever 78 has pivotally connected therewith a rod 114 slidable in an opening in the contact strip 110 and provided at its upper end with a head 115 so disposed that when the lever 78 swings to a position in which it closes the dampers 72, the contact 110 will be forced into engagement with the contact 111 thereby short circuiting the secondary circuit of the transformer 103, whereupon the magnets 101 and 102 become deenergized and the switches cooperating therewith automatically open, under the action of the springs 99 and 100, thereby breaking the circuits in which the motors 85 and 86 are interposed.

The control of; the motors and the dampers I2 may,'ii' desired, be efiected in other ways than thatshown in Fig. 7 and above described. For example, such control may be eifected electrical- 1y, as for example as disclosed in Fig. 8. In this 135 arrangement instead of employing pneumatic means as shown in Fig. '7, I employ a solenoid 116 the core of which represented at 117 is connected, through a link 118, with the link 75 connecting together the several dampers 72, the M9 I ing figures I employ at the same locations as de 15% desired.

scribed '01 the devices 84, fusible-link circuitbri 1: 5 devices 119 disposed in series in circuit with'the solenoid 116, the latter being shown as supplied with current from the transformer 103, where the source of supply of current is alternating current, and arranged in, circuit with the electromagnets 101 and 102. Where the source of current-supply is direct current, any suitable resistance element is substituted for the,trans'- former 103 to reduce the voltage to the degree It will be understood from the foregoing that should the temperature at any one of the devices 119 be suflicient to fuse the fusible element thereof, the secondary circuit and in which the magnets 101 and 102 and the solenoid 116 are interposed will become broken whereupon the motor switches will automatically open causint;

the motors to stop and the dampers '12 will auto-' matically move to closed position.

It will be noted that the arrangement of the valves above referred to controlling the inlet of the products of combustion, whether diluted or not, and the air, at atmospheric temperature, through'the'inlet 39, into the mixing chamber, operate, under the control of the temperature controlled means, to maintain approximately the same volume and pressure of the mixture of the air and hot gases in the mixing chamber at all I times which makes for substantially uniform temperature regulation.

While I have illustrated and described certain embodiments of nry invention, I do not wish to be understood as intending to limit it thereto as the T same may be variously modified and altered without departing from the spirit of my invention.

What I claim as new, and desire to secure by Letters Patent, is:

1. In dr'yingapparatus, the combination of a member presenting a space to receive material to be dried, a drying gas mixing chamber having an opening directly to the atmosphere, a furnace, a conduit to conduct products of combustion from the furnace to said chamber, a jacket for said conduit having an opening to the atmosphere and arranged to conduct air along the outer surface of said conduit and into said chamber, said conduit and jacket having a common opening into said chamber, a hot gas damper controlling said common opening, a cool air damper controlling said first named opening, means to conduct gases from said chamber to the space in said member, and thermostatic means influenced by heatcondition in said space connected to simultaneously and oppositely move said dampers.

2. In a drying apparatus, the combination of, a member presenting a space to receive material to be dried, a drying gas mixing chamber having an opening directly to the atmosphere, an air mea re damper for said opening a furnace, a draft damper therefor, a conduit to conduct hot prod-. nets of combustion from said furnace and opening 1 into said chamber, a hot gas damper for said last named conduit, common actuating means for all of said dampers connected to simultaneously move said draft and hot gas dampers in an opposite direction between open and closed positions from the similar movement of the air damper, and thermostatic means influenced by heat condition in said space for controlling said actuating means,

whereby to preserve substantially constant the volume of flow of drying gas to said space and to regulate the temperature in said space.

3. In a drying apparatus, the combination of a member presenting a space to receive material to be dried, a drying gas mixing chamber having an opening directly to the atmosphere, a. furnace, means to conduct products of combustion from said furnace having an opening into said chamber, separate dampers for each of said openings, actuating means so connected to each of said dampers as to oppositely move the same toward opening and closing respectively, thermostatically controlled means responsive to heat change in said space to move said actuating means whereby to preserve the volume of flow of drying gas to said space substantially constant while regulating the temperature thereof, a conduit to conduct drying gas from said chamber to said space, a damper in said conduit, and means responsive to a degree of heat in said space above a predetermined temperatureto cause complete closure of said last named, damper.

4. In a drying apparatus, the combination of a member presenting a space to receive material to be dried, a drying gas mixing chamber having an opening directly to the atmosphere, a furnace, means to conduct products of combustion from said furnace having an opening into said chamber, separate dampers for each of said openings, actuating means so connected to each of said dampers as to oppositely move the same toward opening and closing respectively, thermostatically controlled means responsive .to heat change in said space to move said actuating means whereby to preserve the volume of flow of drying gas to said space substantially constant while regulating the temperature thereof, a conduit to conduct drying gas from said chamber to said space, a damper in said conduit, a fan in the line of said conduit to provide a force feed of said drying gas, means in said space responsive to a degree of heat in excess of a predetermined temperature to cause complete closure of said last named damper, and means set into action by said excess heat responsive means to cause stoppage of said fan.

BRYCE M. HESS. 

